Rejection-type cartridge fuse clip

ABSTRACT

A rejection-type fuse clip for ferrule type cartridge fuses. The rejection feature of the clip is provided by a single music-wire piece that is suspended between the arms of the clip so that a curved central part of the piece is movable with a swing-like motion between the arms of the clip and receivable in an annular groove in a ferrule on one end of a fuse to permit fuses having grooved ferrules to be inserted between the contact surfaces on the arms of the clip and prevent fuses having ungrooved ferrule ends from being installed between the contact surfaces. The movable central part permits the ferrule to be rotated in the clip without deforming or destroying the rejection feature of the clip and maintains the fuse in a position where it extends perpendicular to the base of the clip when the fuse is positioned in the clip to interrupt its associated circuit.

United States Patent Puetz Inventor:

Assignee:

Filed:

REJECIION-TYPE CARTRIDGE FUSE CLIP Jordan F. Puetz, Milwaukee, Wis.

Square D Company, Park Ridge, 111.

Oct. 3, 1974 Appl. No.: 511,889

US. Cl. 339/258 F; 337/225 Int. Cl. HOIH 85/20; l-IOIH 85/24 Field of Search 339/150 F, 219 F, 252 F,

339/253 F, 256 C, 258 F, 259 F, 262 F; 337/215, 225

References Cited UNITED STATES PATENTS 1 Dec. 23, 1975 Primary Examiner-Roy Lake Assistant Examiner-Neil Abrams Attorney, Agent, or Firm-William H. Schmeling; Harold J. Rathbun [57] ABSTRACT A rejection-type fuse clip for ferrule type cartridge fuses. The rejection feature of the clip is provided by a single music-wire piece that is suspended between the arms of the clip so that a curved central part of the piece is movable with a swing-like motion between the arms of the clip and receivable in an annular groove in a ferrule on one end of a fuse to permit fuses having grooved ferrules to be inserted between the contact surfaces on the arms of the clip and prevent fuses having ungrooved ferrule ends from being installed between the contact surfaces. The movable central part permits the ferrule to be rotated in the clip without deforming or destroying the rejection feature of the clip and maintains the fuse in a position where it extends perpendicular to the base of the clip when the fuse is positioned in the clip to interrupt its associated circult.

7 Claims, 5 Drawing Figures REJECTION-TYPE CARTRIDGE FUSE CLIP This invention relates to fuse clips for cartridge fuses and more particularly to fuse clips having a means which will prevent insertion of improper fuses in the clip and permit the fuse to be rotated to a position where it interrupts a circuit without damaging the clip.

Rejection type fuses and fuse clips incorporating means for receiving the ends of rejection type fuses are well known, as illustrated by the U.S. Pat. No. 2,943,295, which was granted on June 20, 1969 to Vincent N. Stewart. As disclosed in the Stewart patent, the rejection feature incorporated in the clip includes a rigid metal piece which extends forwardly from the base of the clip so a cartridge fuse not having a groove in a cylindrical ferrule at one end of the fuse cannot be inserted between the contact surfaces of the clip. The metal piece in the Stewart clip also includes arcuate edges which are received in the groove in the ferrule. This feature will cause the clip to be deformed when the fuse is pried from the clip in a direction other than perpendicular to the base of the clip. The rejection feature of the Stewart fuse clip also is susceptible to defeat when the fuse is axially displaced to a position in the clip where only the portion of the ferrule extending between the groove and the end of the ferrule is positioned between the contact surfaces on the arms of the clip.

The fuse clip according to the present invention incorporates an improved rejection means which eliminates the disadvantages of prior art structures and incorporates improved rejection means and features not heretofore present in the prior art fuse clip structures.

It is an object of the present invention to provide a fuse clip with a means which will prevent improper cartridge type fuses from being inserted in the clip and which will not be deformed when fuses are inserted into the clip.

Another object is to provide a fuse clip with a means which will prevent improper cartridge-type fuses from being inserted into the clip and will maintain the fuse in the clip when the fuse is rotated to a position where the axis of use is at an angle relative to the base of the clip.

An additional object is to provide a fuse clip with a wire-like piece that is suspended between the arms of the clip so a central curved portion of the piece is movable between the arms with a swing-like motion and is receivable in an annular groove in one of the ferrules of a cartridge-type fuse and arranged to prevent fuses not having a groove in one of its ferrules from being inserted into the clip.

Further objects and features of the invention will be readily apparent to those skilled in the art from the following specification and from the appended drawing illustrating a preferred embodiment, in which:

F IG. 1 is a side elevational view of a pair of fuse clips supporting a fuse with one of the fuse clips incorporating the features of the present invention.

FIG. 2 is a side view of the fuse clips and fuse in FIG. 1 with the fuse detached from one of the fuse clips and supported solely by the fuse clip incorporating the features of the present invention.

FIG. 3 is a perspective view of a portion of a cartridge-type fuse having a rejection feature as detached from a fuse clip shown in perspective that incorporates the features of the present invention.

FIG. 4 is a cross-sectional view taken along line 4-4 in F l6. 3, and

FIG. 5 is a side view of the clip shown in FIG. 3.

While rejection-type fuses have been available for many years, their use was limited due to the lack of standardization of the fuses manufactured by the various fuse manufacturers. More recently, because of higher available fault current associated with the increased size of electrical systems, it became necessary that the proper size as well as the proper type fuses be used as replacements in electrical systems. This requirement has been incorporated into the National Electric Code which requires properly selected overcurrent devices be used to interrupt short circuits and that fuse holders for current limiting fuses be so designed that non-current limiting fuses cannot be installed in fuse holders that are designed to accept current limiting type fuses. To implement this requirement, Underwriters Laboratories, Inc. has developed test standards to assure that both the fuse holders and fuses meet the code requirements and remain a continuing performing combination. One type of an Underwriters Laboratory approved current-limiting cartridge fuse, known as Class R fuse, is sized to be used in 0-60 ampere circuits and includes a rejection feature which is provided by an annular groove located in a precise distance from the end of one of the ferrules on the fuse. The fuse clip according to the present invention is designed to be used with this type of fuse and reject fuses not having an annular groove in one of its end ferrules.

[n the drawings, a Class R cartridge type fuse 10 having a size ranging from 0 to amps has a pair of cylindrical metal ferrules l2 and 14 at its opposite ends. One of the ferrules 14 has an annular groove 16 located from an end 17 of the ferrule. The other ferrule 12 does not have a groove therein. In FIGS. 1 and 2, a pair of fuse clips 18 and 20 are shown as mounted a predetermined distance apart on a support 22. The size and space between the clips 18 and 20 is dependent upon the size of the fuse 10 which they are designed to accept. While in the embodiment shown and described the support 22 is depicted as a vertical panel with the clip 18 mounted at the upper end of the panel and the clip 20 mounted at the lower end of the panel, the panel may be oriented in a position other than vertical if required, without departing from the scope of the present invention. The clips 18 and 20 are identical with the exception that the clip 20 includes a means which will permit the clip 20 to prevent ungrooved ferrules from being inserted between its arms as will be hereinafter described, while the clip 18 does not include a rejection means so the clip 20 will accept ungrooved ferrules between its arms.

The fuse clip 20 includes a main body 24 formed of a highly conductive resilient material to have a base 26 and a pair of upstanding spaced generally parallel flexible arms 28 extending forwardly from the opposite sides of the base 26. The base 26 has an opening 30 which may be used to accept a rivet or screw, not shown, to mount the clips 18 and 20 on the support 22.

The arms 28 have outwardly curved portions defining opposing concave contact surfaces 32 respectively for engaging opposite sides of the ferrule 14. The curvature of the contact surfaces 32 enables the arms 28 to contact as much of the cylindrical surface on ferrule 14 as possible to assure good electrical contact with the ferrule 14 to minimize the heating effects of the electrical connection therebetween.

The contact surfaces 32 extend forwardly to the free ends on the arms 28 which are outwardly turned over to provide rolled-over portions 34 at the free ends of each of the pair of arms 28. Extending rearwardly through the rolled-over portions 34 and into a portion of the contact surfaces 32 in each arm 28 is a slot 36. The slots 36 in the arms are located a predetermined distance from an end 38 in their associated arm 28 and extend rearwardly to provide a U-shaped root portion 40 that is spaced rearwardly of the rolled-over portions 34. A wire-like interference member 42 is suspended between the pair of arms 28 by pivot portions 44 which are located at opposite ends of the member 42 and positioned in the root portions 40. The member 42 is preferably formed of music wire, which inherently resists being cut by conventional cutting tools which would be used to defeat the rejection feature of the clip 20, and is formed to have a central portion 46 extending between the pivot portions 44. The portion 46 is curved to have a semi-circular shape and is received within the groove 16 when the ferrule 14 is positioned between the contact surfaces 32 on the fuse clip 20.

A stop 48 is provided by a wire-like piece. The stop 48 is preferably formed of material such as steel, having relatively good spring qualities, and has end portions 50 firmly secured below the rolled-over portions 34. The end portions 50 extend below the rolled-over portions 34 from the end 38 a sufficient distance to close the front ends 38 of the slots 36 to thereby maintain the pivot portions 44 in the slots 36.

Extending rearwardly from the end portions 50 is a portion 52 which is substantially V-shaped and spaced a predetermined distance from the end 38. The portion 52 has a pair of arm portions extending from the end portions 50 to an apex 56 which is rounded so as to resist the separation of the arms 28 as well as act as a stop as will be later disclosed. Further, the construction of the stop 48 is such that it affords the proper spring action to permit the contact surfaces 34 on the arms 28 to spring into and out of engagement with the ferrule 14.

The pivot portions 44 are essentially U-shaped with one of the arm portions extending as a continuation of the portion 46 from the bight portion 58 which is received in the slot 36 and the other arm portion 60 extending rearwardly from the bight portion 58 along the outer surfaces of the arms 28. The bight portions 58 are received with clearance in the root portions 40 so the pivot portions 44 will permit the portion 46 to be movable between the pair of arms 28 with a swing-like motion.

The fuse clips 18 and 20 are spaced on the support 22 to locate the stops 48 on the clips 18 and 20 so the end on the ferrule 12 is adjacent the stop 48 on the clip 18 and the end 17 on the ferrule 14 is adjacent the stop 48 on the clip 20 when the fuse 10 is positioned for insertion into the clips 18 and 20. When the fuse 10 is thus positioned by the stops 48 for insertion into the clips 18 and 20, the groove 16 on the ferrule 14 will be aligned to receive the portion 46 to permit the ferrule 14 to be moved into position between the contact surfaces 32 as the arms 28 flex outwardly. The portion 46 is movable with a swing-like motion between the arms 28. Thus during insertion of the ferrule 14 into the clip 20, a portion of the groove 16 will initially engage the ends of the portion 46 adjacent the pivot portions 44 and cause the portion 46 to automatically swing to a position where it is aligned to be received in the groove 16 as the ferrule 14 is inserted between the arms 28 to a position where it engages the contact surfaces 32. In event an attempt is made to insert an ungrooved ferrule into the clip 20, the portion 46 will be positioned to engage ungrooved portions of the ferrule and prevent the ferrule from moving between the arms 28 to a position where it engages the contact surfaces 32.

While fuses are not intended to be used as switches to complete or interrupt a circuit, the fuse clip 20 according to the present invention may be used to position its associated fuse in a position where the fuse 10 is disengaged from the fuse clip 18 and positioned in the fuse clip to interrupt the circuit between the fuse clips 20 and 18. When the fuse and fuse clip assembly shown in FIG. 1 is installed, preferably the fuse clip 18 is connected to the line side of a circuit and the fuse clip 20 to the load side of the circuit so that when the fuse 10 is positioned as shown in FIG. 1, a circuit is completed between the fuse clips 18 and 20. If it is desired to maintain the circuit associated with the fuse 10 in an interrupted condition after the circuit is deenergized by a separate switching means, the fuse 10 is moved from the position shown in FIG. 1 to the position shown in FIG. 2 by prying the ferrule 12 from its position between the arms 32 of the fuse clip 18 and pivoting the ferrule 14 in the fuse clip 20 to the position shown in FIG. 2. During the pivotal motion of the fuse 10, the wire-like member 42 will remain in the groove 16 as the rotation of the ferrule 14 in the fuse clip 20 causes an outward flexure of the arms 28 on the fuse clip 20. When the fuse is in its final position, as shown in FIG. 2, the fuse 10 will extend vertically of the base 26 and will be firmly maintained in the vertical position by the wire-like member 42 which is received in the upper side of the groove 16 and end portions on the lower ferrule 14 which are positioned on portions of the arms on the wire-like member 42 to prevent removal of the fuse from the vertical position shown in FIG. 2 will be prevented by the arm portion which engages the under side of the rolled-over portions 34. When it is desired to return the fuse 10 to the position shown in FIG. 1, while the circuit is de-energized, all that is required is to rotate the fuse in the fuse clip 20 to a position where the ferrule 12 is received between the arms 28 of fuse clip 18 which spread slightly as the fuse 10 is inserted between the arms.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What is claimed is:

l. A fuse clip for releasably engaging a cartridge fuse of the type having cylindrical ferrules at the opposite ends thereof with one of the ferrules having an annular groove comprising: a pair of spaced generally parallel flexible clamping arms providing a pair of spaced eonfronting curved contact surfaces for engaging opposite sides of the grooved ferrule and a wire-like member suspended between the arms, said member having a curved portion positioned in the space between the pair of contact surfaces to be received in the groove when a grooved ferrule is positioned between the curved contact surfaces and providing an obstruction for preventing the insertion of any ferrule on a fuse not provided with an annular groove.

2. The fuse clip as recited in claim 1 wherein the clip includes a portion spaced from the member and providing a stop for limiting the axial displacement of the grooved ferrule in one direction when the grooved ferrule is positioned between the contact surfaces.

3. The fuse clip as recited in claim 2 wherein the member is suspended between the arms so curved portion is movable with a swing-like motion in the space between the arms.

4. The fuse clip as recited in claim 3 wherein the clip has a base extending between the arms and the portion providing the stop is spaced from the curved portion so the curved portion is received in the groove and end portions on the ferrule engage portions on the stop for maintaining the ferrule in a position between the arms after the ferrule is rotated from a position where it is engaged by the contact surfaces to a position where the axis of the ferrule is at an angle relataive to the base.

5. The fuse clip as recited in claim 2 wherein the member providing the stop is a resilient wire-like piece having ends secured to free end portions of the arms and a V-shaped mid portion extending between the ends of the member.

6. The fuse clip as recited in claim I wherein the wire-like member is formed of stiff music wire.

7. A fuse clip for releasably engaging a cartridge type fuse having cylindrical ferrules at the opposite ends thereof with one of the ferrules having an annular groove spaced from the end of its associated ferrule, comprising; a base, a pair of spaced generally parallel flexible clamping arms extending forwardly from opposite side edges of the base, said arms having opposed oppositely curved contact surfaces for engaging opposite sides of the grooved ferrule, an outwardly turned rolled-over portion at the free ends of each of said arms and a slot extending rearwardly toward the base in each arm through the rolled-over portion to a U-shaped last portion located rearwardly of the rolled-over portion, a wire-like member suspended between the arms said member having a curved central portion received within the groove when a grooved ferrule is positioned between the contact surfaces, pivot portions at opposite ends of the central portion positioned in the U- shaped root portion of the pair of arms for permitting the curved portion to be movable between the arms with a swing-like motion and portions extending from the root portions rearwardly adjacent the arms for preventing displacement of the member from the root portions, and a wire-like piece providing a stop, said piece having ends secured within the rolled-over portions and closing the front ends of the slots for maintaining the pivot portions in the root portions and a V-shaped midportion extending between the ends of the piece and spaced from the curved central portion of the member for preventing axial displacement of the grooved ferrule in one direction to a position where a ferrule not provided with a groove may be positioned between the curved contact surfaces.

i I 1! 1k 1! UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,927,929 Dated December 23, 1975 Invenmfl Jordan F. Puetz It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

C01. 1, line 11, "1969" should read --1960--. C01. 2, line 2 cancel 'in" before --a--. Col. 4, line 39, after "fuse" insert ---10 from the fuse clip 20. Further downward movement of the fuse Col. 5, line 7, after "so" insert --the--;

30, cancel semicolon and insert colon (z). C01. 6, line 7, cancel "last" and insert --root--.

Signed and Scaled this Twenty-fourth Day Of August 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Amm'ng Offl'cer Commissr'nner oj'larenrs and Trademarks 

1. A fuse clip for releasably engaging a cartridge fuse of the type having cylindrical ferrules at the opposite ends thereof with one of the ferrules having an annular groove comprising: a pair of spaced generally parallel flexible clamping arms providing a pair of spaced confronting curved contact surfaces for engaging opposite sides of the grooved ferrule and a wirelike member suspended between the arms, said member having a curved portion positioned in the space between the pair of contact surfaces to be received in the groove when a grooved ferrule is positioned between the curved contact surfaces and providing an obstruction for preventing the insertion of any ferrule on a fuse not provided with an annular groove.
 2. The fuse clip as recited in claim 1 wherein the clip includes a portion spaced from the member and providing a stop for limiting the axial displacement of the grooved ferrule in one direction when the grooved ferrule is positioned between the contact surfaces.
 3. The fuse clip as recited in claim 2 wherein the Member is suspended between the arms so curved portion is movable with a swing-like motion in the space between the arms.
 4. The fuse clip as recited in claim 3 wherein the clip has a base extending between the arms and the portion providing the stop is spaced from the curved portion so the curved portion is received in the groove and end portions on the ferrule engage portions on the stop for maintaining the ferrule in a position between the arms after the ferrule is rotated from a position where it is engaged by the contact surfaces to a position where the axis of the ferrule is at an angle relataive to the base.
 5. The fuse clip as recited in claim 2 wherein the member providing the stop is a resilient wire-like piece having ends secured to free end portions of the arms and a V-shaped mid portion extending between the ends of the member.
 6. The fuse clip as recited in claim 1 wherein the wire-like member is formed of stiff music wire.
 7. A fuse clip for releasably engaging a cartridge type fuse having cylindrical ferrules at the opposite ends thereof with one of the ferrules having an annular groove spaced from the end of its associated ferrule, comprising; a base, a pair of spaced generally parallel flexible clamping arms extending forwardly from opposite side edges of the base, said arms having opposed oppositely curved contact surfaces for engaging opposite sides of the grooved ferrule, an outwardly turned rolled-over portion at the free ends of each of said arms and a slot extending rearwardly toward the base in each arm through the rolled-over portion to a U-shaped last portion located rearwardly of the rolled-over portion, a wire-like member suspended between the arms said member having a curved central portion received within the groove when a grooved ferrule is positioned between the contact surfaces, pivot portions at opposite ends of the central portion positioned in the U-shaped root portion of the pair of arms for permitting the curved portion to be movable between the arms with a swing-like motion and portions extending from the root portions rearwardly adjacent the arms for preventing displacement of the member from the root portions, and a wire-like piece providing a stop, said piece having ends secured within the rolled-over portions and closing the front ends of the slots for maintaining the pivot portions in the root portions and a V-shaped midportion extending between the ends of the piece and spaced from the curved central portion of the member for preventing axial displacement of the grooved ferrule in one direction to a position where a ferrule not provided with a groove may be positioned between the curved contact surfaces. 